Split the driveway into non-overlapping rectangles and triangles. Calculate each area, apply its own gravel depth, then add the volumes.
- Measure the main rectangle: 40 × 10 = 400 sq ft.
- Measure the apron base and perpendicular height: 12 × 8 ÷ 2 = 48 sq ft.
- At 3 inches deep, multiply 448 × 3 ÷ 324 for approximately 1.38 cubic yards before allowance.
If depths differ, calculate each section’s volume separately. For a curved boundary, use smaller measured sections and record that the result is approximate.
How to measure a driveway when the width changes
Sketch the driveway before measuring. Mark where the width changes and separate the straight stretch, widened apron and turnaround. Measure the long straight stretch as a rectangle if its sides are parallel. For a triangular flare, record the base and perpendicular height. If the edge curves, divide it into smaller measured pieces and label your result as approximate.
Measure depth for each driveway section
When every section has the same depth, you can add the areas and calculate volume once. If the main rectangle is 400 sq ft at 3 inches and the apron is 48 sq ft at 4 inches, calculate 400 × 3 ÷ 324 and 48 × 4 ÷ 324 separately. Together that is about 4.30 cubic yards before allowance. Use the depth specified for each section of your project.
Check the measurements before requesting a quote
Keep your sketch and write the units next to each number. Confirm that shared edges have not been counted twice and exclude any areas that will stay uncovered. Use the same measurements to request both bulk volume and weight quotes, with density supplied by the vendor when weight is needed.